Mounjaro (tirzepatide) is a prescription-only medicine licensed in the UK for type 2 diabetes, though it is increasingly sought for weight management through private services such as Hey Slim. Understanding the costs, regulatory requirements, and safe access routes is essential for anyone considering this treatment. This article examines Mounjaro's mechanism of action, the role of online prescribing platforms, pricing structures for NHS versus private prescriptions, and the critical importance of avoiding unregulated sources. All information aligns with current MHRA, NICE, and NHS guidance to support informed decision-making.

What Is Mounjaro and How Does It Work for Weight Loss?

Mounjaro (tirzepatide) is a prescription-only medicine licensed in the UK for the treatment of type 2 diabetes. In the EU, tirzepatide is marketed as Zepbound for chronic weight management. It belongs to a class of medications known as dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists. By activating both of these incretin hormone receptors, tirzepatide offers a mechanism of action that distinguishes it from other medications currently available.

The mechanism of action centres on mimicking natural gut hormones that regulate appetite and glucose metabolism. GLP-1 receptor activation slows gastric emptying, reduces appetite, and enhances insulin secretion in response to meals, while GIP receptor activation further supports glucose control and may influence fat metabolism. Together, these effects lead to reduced calorie intake, improved glycaemic control, and weight loss in clinical trials. Patients typically report feeling fuller for longer periods and experiencing fewer cravings, which supports dietary changes.

Mounjaro is administered as a once-weekly subcutaneous injection, starting at a low dose (2.5 mg) and gradually titrated upwards over several months to minimise gastrointestinal side effects. The maximum maintenance dose is 15 mg weekly. Clinical trials have shown weight reductions varying by dose and patient population, with the SURMOUNT-1 trial demonstrating up to 21% weight loss with the 15 mg dose in people without diabetes over 72 weeks. Results may be lower in people with type 2 diabetes. Treatment must be used alongside a reduced-calorie diet and increased physical activity.

Common side effects include nausea, diarrhoea, vomiting, constipation and abdominal pain. Patients should seek urgent medical attention for severe abdominal pain (with or without vomiting), persistent vomiting causing dehydration, or symptoms of gallbladder problems. Tirzepatide is not recommended during pregnancy or breastfeeding, and may reduce the effectiveness of oral contraceptives—additional barrier contraception is advised for 4 weeks after starting treatment and after each dose increase.

Hey Slim and Online Mounjaro Services: What to Expect

Hey Slim is one of several online healthcare platforms offering access to weight-loss medications, including Mounjaro, through remote consultations with UK-registered prescribers. These digital services have grown in popularity as they provide convenient access to specialist weight management support without the need for in-person GP appointments. However, it is essential to understand what constitutes safe and legitimate online prescribing before engaging with any such service.

Reputable online providers operate within the regulatory framework set by the Medicines and Healthcare products Regulatory Agency (MHRA), the Care Quality Commission (CQC) for service providers in England, and professional bodies such as the General Medical Council (GMC), Nursing and Midwifery Council (NMC), or General Pharmaceutical Council (GPhC) depending on the prescriber's profession. They should require patients to complete a comprehensive medical questionnaire covering medical history, current medications, allergies, and contraindications. A qualified prescriber must review this information and conduct an appropriate assessment to determine suitability. Legitimate services will not issue prescriptions without proper clinical assessment, as this would constitute unsafe practice and breach professional standards.

Once approved, patients typically receive their medication via registered pharmacy partners, with ongoing monitoring and support provided through the platform. This may include regular check-ins, side effect management, and dose adjustments as needed. Key features of legitimate services include:

• Clear information about prescriber qualifications and professional registration numbers

• Transparent pricing with no hidden fees

• Access to clinical support for questions or concerns

• Proper follow-up protocols and safety monitoring

• Clear exclusion criteria and contraindications

Patients should be wary of services that promise instant prescriptions, lack proper medical oversight, or fail to provide adequate information about risks and side effects. The MHRA provides guidance on safely buying medicines online. This information is provided for educational purposes only and does not constitute an endorsement of any specific provider.

Safe Access to Mounjaro: Avoiding Unregulated Sources

The rising demand for weight-loss medications has unfortunately led to a proliferation of unregulated and potentially dangerous sources offering Mounjaro and similar products. The MHRA has issued repeated warnings about counterfeit semaglutide (Ozempic/Wegovy) and tirzepatide products entering the UK market, some of which contain incorrect doses, contaminants, or no active ingredient at all. Purchasing medications from unverified online pharmacies, social media sellers, or overseas websites poses serious health risks and may result in seizure of products by customs authorities.

Genuine Mounjaro can only be legally obtained in the UK through a valid prescription from a registered healthcare professional, dispensed by a registered pharmacy. The medication comes in pre-filled, single-use injection pens with specific branding and packaging that includes batch numbers, expiry dates, and manufacturer information. Patients should verify that their pharmacy is registered with the General Pharmaceutical Council (GPhC) by checking the online register. Any supplier unable or unwilling to provide registration details should be avoided.

The risks of unregulated sources extend beyond counterfeit products. Without proper medical supervision, patients may:

• Receive inappropriate doses leading to adverse effects

• Miss important contraindications or drug interactions

• Lack access to clinical support if complications arise

• Experience allergic reactions to unknown ingredients

• Risk hypoglycaemia, particularly if also taking insulin or sulfonylureas

If you suspect you have received counterfeit medication, stop using it immediately and report it to the MHRA via their Yellow Card scheme. Contact your GP or NHS 111 for advice, particularly if you have experienced any adverse effects. The MHRA also recommends reporting the supplier to help protect others. Remember that if a price seems too good to be true, or if a supplier does not require a prescription, these are significant red flags indicating an illegitimate source.

Mounjaro Cost in the UK: NHS vs Private Prescriptions

The cost of Mounjaro varies significantly depending on whether it is accessed through the NHS or private healthcare services, and this remains a key consideration for many patients seeking weight management treatment. As of 2024, Mounjaro is available on the NHS for type 2 diabetes management in specific circumstances, in line with NICE guidance. However, tirzepatide is not currently routinely available on the NHS for weight loss alone. NHS England and NICE are evaluating its use for obesity treatment, but widespread NHS availability for weight management remains limited pending formal NICE guidance.

For patients accessing Mounjaro privately, costs can vary considerably depending on the dose, provider, and whether consultations are included. This typically covers the medication itself, prescriber consultations, and ongoing clinical support. Services like Hey Slim and other providers often offer tiered pricing structures, with initial months sometimes costing more due to comprehensive assessments and setup fees. The financial commitment should be considered carefully, as treatment duration will affect the overall cost. Some providers offer subscription models or payment plans to make treatment more accessible.

Private prescription costs generally include:

• Initial consultation and assessment fees

• Monthly medication supply (dose-dependent)

• Follow-up consultations

• Delivery and pharmacy fees

It is worth noting that private health insurance policies rarely cover weight-loss medications unless there are significant obesity-related comorbidities. Patients should check their policy terms before assuming coverage. For those unable to afford private treatment, discussing alternative weight management options with your GP is advisable. The NHS offers free access to tiered weight management programmes, dietetic support, and in some cases, alternative medications such as orlistat. For those with severe obesity (BMI ≥40 kg/m² or ≥35 kg/m² with comorbidities), referral to specialist NHS tier 3 services or consideration for bariatric surgery may be appropriate. NICE guidelines recommend that pharmacological treatment should only be considered as part of a comprehensive weight management programme that includes dietary, physical activity, and behavioural interventions.

If you experience any side effects from medication, report them through the MHRA Yellow Card Scheme.

Frequently Asked Questions